It is known in the art relating to engine fuel injectors to provide high pressure injection of fuel directly into the cylinder compressed air charge of a diesel or gasoline engine. So-called accumulator injectors fed with high pressure fuel from a common rail are among those used for this purpose. U.S. Pat. No. 4,826,080 Ganser discloses one form of prior injector for such purpose in which a diaphragm mounted solenoid armature drives a control valve that initiates opening and closing of an injection valve. The injection valve is closed and opened by varying fuel pressure in a control chamber through opening and closing of a depressurizing orifice by the control valve while the control chamber is being supplied through a separate aligned pressurizing orifice. Control of the rates of opening and closing of the injection valve is provided by proper selection of the orifice diameters and other parameters.
One result of this method of electrically controlled hydraulic actuation is the recirculation of return fuel discharged from the depressurizing passage during open periods of the injection valve. Because return fuel flow through the two passages continues until the control valve is again closed, additional high pressure fuel beyond that needed for fuel injection must be pumped for valve actuation purposes requiring larger fuel pump and energy costs. The size and mass of the prior solenoid mounted armature also adds to the energy use and cost.